Mar 27, 2013 - By Eric Blom, Staff WriterA recent inspection by the Wyoming Department of Transportation found damage to a wooden bridge on Ray Lake Road, where one support post was split from top to bottom, and another was leaning inwards.
The officials reduced the bridge's rating to a maximum of 11 tons, which became a cause for concern.
"There's a 17-ton bus that transports children over that bridge," county transportation superintendent Dave Pendleton said.
Ray Lake Road is between Lander and Fort Washakie.
The Ray Lake Road bridge is just one problematic structure, but it is representative of a larger problem of worn-out bridges in Fremont County that the transportation department is working to fix.
"There are 12 bridges that are either structurally deficient or are functionally obsolete," Pendleton told the Fremont County Commission at its March 19 meeting.
WyDOT inspectors two years ago found 12 bridges on county roads that have a sufficiency rating of 50 percent or less. The state agency only examines bridges with a 20-foot span or greater.
Pendleton said once the sufficiency rating is below 50 percent, replacing the bridge should be considered.
Six bridges in Fremont County will see replacements this spring and summer, three of which are among those problematic 12, and a fourth which was rated at 53 percent two years ago. The last two are too small for WyDOT to inspect.
The weakened bridge on Ray Lake Road is among those scheduled for replacement.
"If people go across in a heavy vehicle, they may not go through, but they will cause damage," Pendleton said in an interview.
Because of the potential for further damage, crossing in a vehicle that is too heavy for the structure also endangers subsequent drivers.
The bridge's proximity to Ray Lake Dam will complicate the new build.
Pendleton said a new structure will have to pass a large volume of water coming off the dam from a field and draining from the road. If the culvert is too small, water could back up on the dam and cause damage.
"Well have to oversize it," Pendleton said.
He said his department has submitted plans for that bridge to WyDOT for review.
County transportation also will replace a small nearby bridge on Ray Lake Road. Pendleton expects to use 48-inch culverts in its place.
Large diameter pipe culvert also will be used to replace a small bridge on Harris Road a few miles east of Pavillion.
Old Highway 789
In an interview, Pendleton said the transportation department plans to replace two bridges on Old Highway 789 first.
Also called Hall Creek road, the highway is about 20 miles southeast of Lander.
During a recent inspection, WyDOT discovered a split stringer on a three-span, 71-foot bridge built in 1932.
A stringer is a girder running along the length of the bridge, supporting its deck.
Because of the faulty support, the state agency gave the bridge a maximum load of three tons, or 6,000 pounds. The road sees few cars, but 40-ton cattle trucks use it regularly. Pendleton said.
"You get cattle trucks running over an 80-year-old bridge you're going to break some stringers," Pendleton said at the meeting.
He said the plan is to replace the structure with three concrete pipes measuring 4 feet in diameter, or with a larger-diameter steel culvert.
The transportation superintendent expects to replace a second bridge on Old Highway 789 with pipe as well. Also built in 1932, the bridge is 59 feet long and has three spans.
A third bridge on Old Highway 789 is on the transportation department's list for replacement, but the county department does not have immediate plans for that structure. The bridge is 115 feet long, dates to 1932 and had a sufficiency rating of 45 percent in 2011. Pendleton said more time will be necessary to have an engineer design a replacement for the bridge because it passes a large amount of water for Twin Creek.
Diversion Dam Road
The transportation department has submitted plans for WyDOT approval to build a new bridge on Diversion Dam Road a few miles west of Pavillion to replace the 101-foot bridge crossing the Wyoming Canal. In 2011, WyDOT rated the bridge's sufficiency at 32 percent.
A second bridge on Diversion Dam Road is also in bad shape but sees so little traffic that Pendleton does not think a replacement is warranted. The 717-foot bridge was built in 1925, and in 2011 it received a sufficiency rating of 11.3 percent.
Pendleton said it would probably cost $10 million to $15 million to replace it, but only 10 to 20 cars use the structure daily. He added other roads provide access to both ends of the bridge.
Another bridge on Diversion Dam road is also in bad shape. Pendleton said heavy loads have smashed the tops of the bridge's piles and split them. Attempts to shore up the bridge by strapping metal bands around the piles to compress them have not succeeded, and Pendleton added that the deck has dry rotted.
Pendleton said the Midvale Irrigation District might be using the bridges, but he thought the water district also had access to its facilities along the canal.
Fremont County's infrastructure still has issues, but Pendleton thinks it is improving. He said the replacements this year should be a step in that direction.
"We've made great strides in the last 10 years getting these bridges that are of concern off the system," Pendleton said.
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